Chain saw guard



June 27, 1967 M. E. LONG ETAL 3,327,743

CHAIN SAW GUARD Filed Oct. l1, 1965 \28 IN VEN TORS l m. 5 2/ @fwn E.

BY i f1( M ATTORNEYS United States Patent 3,327,743 CHAIN SAW GUARD Melvin E. Long and Elwood E. Long, Livonia, N.Y. (both of Lakeville, N.Y. 14480) Filed Oct. 11, 1965, Ser. No. 494,331 13 Claims. (Cl. 143-159) This invention relates to a chain saw guard having an improved latch release mechanism.

A chain saw guard is a well known structure. It comprises a protective sheath or shield for enclosing at least the side and generally the top and front or outer end of the saw chain. The sides of the shield, when in protective position, generally project both upwardly and downwardly relative to the saw chain. Means are provided for pivotally mounting the shield `on the chain saw. These means enable the shield to pivot out of protective position when the saw chain is brought into contact with work to be cut. Generally there is a spring which returns the shield to its protective position when the chain saw is removed from the work. Latch meansV are usually present for locking the shield in its protective position when the chain saw is not being used. To unlock the shield, there is a latch release mechanism.

Heretofore the latch release mechanism has comprised a manually operated lever pivotally mounted on the saw chain frame near one of the handles, usually the rear one, by which the chain saw is gripped and held under use conditions. The lever arm is 4connected by a moveable, iiexible cable to a slidable pin or to a pivotally mounted catch of the latch means, which pin or catch in one position locks the shield and, when moved out of that position, unlocks the shield.

One disadvantage of this kind of latch release mechanism is that it must be manually operated. This is inconvenient, awkward and slow.

Another disadvantage of this kind of latch release mechanism is the tendency for the tiexible cable to break. Also, this kind of latch release mechanism is diicult to adapt to different makes of chain saws.

An object Iof this invention is to provide a chain saw `guard having a latch release mechanism that avoids these disadvantages.

More generally, an object of this invention is to provide a chain saw guard having an improved latch release mechanism.

These and other objects which may appear as this specication proceeds are achieved by this invention which, in summary, comprises a chain saw -guard with latch release means which can be actuated by the operator rapidly, conveniently and with easy and natural motion. According to this invention, the latch release means function as a result of the chain saw and thus the guard .being moved so as to bring a moveable element of the latch release means, which is in the region of the front end of the guard, into contact with a relatively immoveable object such as, -for example, the work to tbe cut, with suiicient force to move the element from a iirst position to a second position whereat the latch release means unlatch the latch means.

This invention is further described in relation to the drawing which forms a material part of the disclosures of the invention. In the drawing:

FIG. 1 is a top view of a preferred specific embodiment of a chain saw guard according to this invention, the moveable parts thereof being in latched position;

FIG. 2 is a side view of the specific chain saw guard of FIG. 1, which guard is mounted on a chain saw, part of which is shown in phantom;

FIG. 3 is a view of a longitudinal section of the chain saw guard of FIG. l, which view has been taken as indicated lby the sectioning plane 3-3 in FIG. 1;

3,327,743 Patented .lune 27, 1967 `Ice FIG. 4 is a view of the longitudinal section of FIG. 3 as it appears when the shield of the chain saw guard of FIG. 1 is in rest position;

FIG. 5 is a view of a cross section of the chain saw -guard of FIGS. 1 and 2, which view has been taken as indicated by the offset sectioning plane 5 5 in FIG. 2.

Structure In greater detail, FIGS. l-5 illustrate a chain saw lguard 10 according to this invention, which, Vunder normal use conditions, is mounted on a chain saw so as to enclose the saw chain 12 (see FIG. 2), except when, and normally only as, a work piece is being cut by the chain saw. In the embodiment shown in FIG. 2, the chain saw guard 10 is fastened as by bolts to the saw chain support 11 in the region of its inner or back end, that is, the end closest to the chain saw motor, frame, and lift bars.

The chain saw guard 10 comprises saw chain shield means 13 and pivotal mounting means 14 for mounting the shield means on a chain saw. Relative to the saw chain 12, when the chain saw guard lo is mounted on a chain saw, the shield means 13 can be pivoted from a latch position, in which position the shield means enclose the saw chain, to a second position adjacent the iirst position and referred to herein as the unlatched, rest position, Where the shield means still enclose the saw chain, and, continuing in the same direction of rotation, to a limit position where the saw chain is substantially completely exposed and where it can .lbe embedded in a work piece, such as a log and the like. The limit position is determined by either the chain saw structure or guard structure other than the shield means 13, depending on which blocks the shield means 13 first in pivoting in said direction of rotation. In addition to the shield means 13 and pivotal mountlng means 14, the chain saw guard 10 comprises means 16 for urging the shield means 13 to at least the unlatched, rest position, latch means 1S for latching the shield means 13 in latch position, means 20 for urging said latch means to latch the shield means 13 when in the latch position, latch release means 22, and means 24 for urging the shield means 13 from said latch position toward said rest position. The saw chain shield means 13 comprise a shield which 1s an elongated internal structure (see FIGS. l and 2) having a pair of side walls 26 and 28, a top wall 30, and Va front or outer end wall 32. In the embodiment shown, the Ishield is molded from a fiber glass reinforced polyester resin composition. The side walls 26 and 28 are longitudinally disposed and generally parallel and spaced from one another. They merge curvingly into the top wall 30 and the front wall 32. The shield is open at the bottom thereof and at the back or inner end thereof. However, the side walls 26 and 28 project beyond the bottom run of the saw chain 11 when the shield is in latched position.

The pivotal mounting means 14 involves a hinge structure. The hinge structure comprises a shield support bracket 34, :a mounting bracket 36, and a hinge pin 38.

The shield support bracket 34 is in cross section (see FIG. 5) generally channel shaped, having a web 40 and spaced legs 42 and 44. The spacing between legs 42 and 44 of the bracket' is such that the bracket lits into the upper, back end region of the shield with the web 4t) adjacent the underside of the top Wall 30 of the shield and the legs 42 and 44 adjacent the inne-r sides of the side walls 26 and 28 of the shield (see FIGS. 3 and 5). The side walls 26 and 28 of the shield are fastened as by rivets to the legs 42 and 44. The legs 42 and 44 of the shield support bracket 34 comprise ears 46 and 47 (see FIG. l). The ears 46 and 47 are oppositely disposed and extend in the planes of the respective legs 42 and 3 44 backwardly from the back end of the shield. Moreover, each of ears 46 and 47 has a hole therethrough for receiving in sliding lit the hinge pin 38.

The mounting bracket 36 comprises a scroll portion 48 (see FIG. 3) joined to a web portion 50 having a pair lof downwardly extending mounting legs 52 and 54, and an upwardly extending keeper ange 56 with a latch bolt hole 57 therethrough. Both the scroll portion 48 and the hinge pin 38 have coinciding, transverse bores therethrough and, seated in the bores, an anchor pin 38 (see FIGS. 1 and 3). The web portion 50 of the mounting bracket 36 is generally subjacent the Web portion 4t) of the shield suppo-rt bracket when the shield is in latch position. In the embodiment shown, the legs 52 and 54 of the mounting bracket 36 are disposed on each side ofthe saw chain support 11 and are bolted thereto when the chain saw guard is mounted on a chain saw. It is within the concepts of this invention, however, to fasten the mounting legs 52 and S4 to other suitable parts of the chain saw. The web 40 of the shield support bracket 34 has an opening 59 therethrough of size and shape selected to accommodate the keeper flange 56 throughout the path of movement of the shield means 13 under normal operative conditions.

The means 16 for lurging the shield means 13 when out of latch position to at least unlatched, rest position, comprises `a coil type, compression, return spring 60 and a stud 61 (see FIGS. 2 and 5). The stud 61 is mounted on a leg 42 of the shield support bracket 34, being fastened thereto as by weldment or rivet and extending laterally outwardly from the leg 42. The shield side wall 28 has an aperture 62 at the normally upper back end region thereof for the stud 61. The outer end 63 of the return spring 60 is normally -turned outwardly and back (see FIG. 2), forming a reverse curved portion which, when in position, is disposed around the stud 61 and held thereby. The inner end 64 of the return spring 60 is turned inwardly (see FIG. 2) and is normally seated in a slot 6'5 (see FIG. l) through a laterally projecting end -portion of the hinge pin 38 of the hinge. The laterally projecting end portion of the hinge pin 38 is on the same side of the chain saw guard 10 as the stud 61 and the spring 60 is arranged when in position so `as to be stressed when the shield support bracket 34 :and shield means 13 are pivoted away from the mounting bracket 36. Preferably, when the shield is in latch position as in FIGS. 1-3 and 5, the return spring 60 is under substantially no stress.

The latch means 18 for latching the shield means 13 in latch position comprises a slideable latch Ibolt 66 and a housing 67. The housing 67 is fastened to the web 40 of the shield support bracket 34 and extends normally upwardly through an aperture in the top wall 30 of the shield. The latch bolt 66 is slideably disposed through holes at each end of the housing 67 and has front and back end portions 68 and 69 projecting outwardly therefrom. With the shield in latch position, the keeper ange 56 of the mounting bracket 36 is disposed -adjacent the front end of the housing 67, and the front end 68 of the latch bolt 66 is normally seated in the latch bolt hole 57 through the keeper flange 56.

The means 26 for urging the latch means 18 to latch the shield means 13 when in latch position comprise a latch spring 70 and a stop ring 71. The latch spring 70 in the embodiment shown is ia spiral type compression spring :disposed on the latch bolt 66 within the hou-sing 67. The stop ring 71 is seated in an annular groove about the latch bolt 66 within the housing 67 adjacent to the front end thereof and the front end 68 of the latch bolt 66, and projects radially outwardly from the latch bolt 66, providing an annular surface against which the front end of the latch spring 70 bears. The stop ring 71, instead of being seated in an annular slot in the latch bolt 66, can be part of the latch bolt 66 as an annular, radially extending ange. The latch spring 70 is preferably normally in a state of compression, whereby it biases or urges the latch bolt 66 toward the latch position, that is to say, frontwardly, extended outwardly.

The latch release means 22 corn-prise a latch release rod 72, a front end bracket 73, a pair of top brackets 74 and 75, and ya link arm 76.

The latch release rod 72, preferably disposed outside the shield, has an end portion 78 and a longitudinal portion '79, the end portion 78 being generally transverse to the longitudinal portion 79. The end portion 78 is generally parallel to the front end wall 32 of the shield while the longitudinal portion 79 of the latch release rod 72 is generally parallel to the top 30 of the shield. The end portion 78 of the latch release rod, when the shield means 13 are in latch position and latched by the latch means 18, is in a first position outwardly spaced from the front end wall 32 by at last a distance the latch bolt 66 must travel backwardly from its latch position to be unseated from the keeper flange 56.

The front end bracket 73, fastened as by rivets to the front end wall 32 of the shield, has an outwardly extending -flange 80 with a guide slot 81 therethrough. The end portion 78 of the latch release rod 72 extends downwardly through the guide slot. The guide slot 81 is slightly wider than the part of the end portion 78 of the latch release rod 72 extending therethrough, while it is sufficiently long to accommodate the longitudinal travel of the end portion 78 of the latch release rod 72 from its irst position to a second position whereat the latch bolt 66 becomes free of the keeper ilange 56.

The top brackets 74 and 75 are fastened as by rivets to the top wall 30 of the shield, one, 74, being in the region of the front end of the shield, and the other, 75, being in the region of the back end of the shield. Each top bracket 74 and 75 has an upwardly extending flange 82 with an aperture 83 therethrough in which normally slideably disposed is the longitudinal portion 79 of the latch release rod 72.

The link arm 76 is a rigid element having a hole therethrough adjacent each end thereof and is normally disposed in a transverse position. The back end of the latch release rod 72 terminates in a threaded stud 84 which is disposed through one of the holes of the link arm 76 and, by means of a nut fastener 85 threadedly engaged ltherewith, is connected to the latch release rod 72. The back end 69 of the latch bolt 65 is disposed through the other hole of the link arm 76 and is fastened to the link arm 76 by means of a split retention ring 86 seated in an annular groove in the back end portion of the latch bolt 66 rearwardly of the link arm 76.

The means 24 for urging the shield means 13, when in latch position, to rest position, comprise a pad of resilient material such as, for example, sponge rubber, flexible polyurethane foam and the like. The pad is disposed between the top side of the web 50 of the mounting bracket 36 and the underside of the web 40 of the shield support bracket 34, and preferably is bonded as by an adhesive to one of said webs. The thickness and resiliency of the pad 24 are selected so that when the shield support bracket 34 and mounting bracket 36 are in latch position relative to one another, the pad 24 is compressed between them, and when the brackets are released from latch position, the brackets 34 and 36 are forced apart just suiciently so that the latch bolt 66 is out of alignment with the bolt hole 57 inthe keeper flange 56 and, therefore cannot slideably seat into the bolt hole'57'. If the return spring 60 is compressed when the shield means 13 is in latch position, the force exerted by pad 24 must be suicient to overcome the opposing force of spring 60 to the point whereat the latch bolt 66 is out of alignment with the latch bolt hole 57.

The means 24 for urging the shield means 13 from latch position to rest position can comprise a spring instead of, or in addition to, a resilient pad. For example,

a spiral-type compression spring can be used. Such a spring can be arranged with its axis generally perpendicular to the web 50 of the mounting bracket 36 with on end of the spring disposed in and bearing against a housing mounted on the web 40 of the shield support bracket 34. The other or bottom end of the spring bears against an annular flange of an axially aligned pin projecting beyond the bottom end of the spring and out of the housing through a suitable opening in the web 40 of the shield support bracket 34 to bear against the web 50 of the mounting bracket 36 when the brackets are in latch position. Such a spring has suflicient compressive strength to separate the shield support bracket 34 and the mounting bracket 56, and urge the shield means 13 from the latch position to the rest position when the latch is released so that the latch bolt 66 will remain disengaged from the keeper flange 67. Also, such a spring overcomes to the extent of the unlatched, rest position any oppositely directed force by the return spring 60.

Operation With the chain guard mounted, for example, on the saw chain support 11 of the chain saw, with the shield means 13 in the latch position as in FIGS. l-3 and 5, and with the chain saw in operation, the operator moves the chain saw so that the end portion 78 of the latch release rod 72 is pressed against a relatively immovable object, for example, the piece to be cut, with suicient force to move the latch release rod 72 longitudinally backwardly and, because of the link arm 76, the latch bolt 66 longitudinally backwardly, a suiiicient distance to unseat the outer end 68 of the latch bolt 66 from the latch bolt hole 57 of the keeper ange S6. The resilient pad 24, being under compression, pushes the shield support bracket 34 away from the mounting bracket 36, placing the shield means 13 in unlatched, rest position and the latch bolt 66 out of alignment with the latch bolt hole 57 of the keeper flange 56. The operator thereupon commences to make the cut.

As the saw chain 12 bites into the work to be cut, the shield is pivoted upwardly, causing the return spring 60 to be stressed, the force of this spring 60 becoming greater the further the shield is pivoted away from the unlatched, rest position.

Upon removal of the chain saw from the work as when the cut has been completed, the force of the return spring 6i) causes the shield means 13 to pivot back toward the rest position. Momentum of the pivoting shield means 13 plus any residual force in the return spring 66 causes the shield 13 to override the resistance of the resilient pad 24 and the latch spring 70 sufciently to bring the shield to the latch position and outer end 68 of the latch bolt 66 into alignment with the latch bolt hole 57 through the keeper iiange 56, whereupon the outer end 68 of the latch bolt 66 pops into position in the latch bolt hole 57, latching the shield means 13 into the protective or saw chain enclosed position.

The chain saw guard of this invention has an inherently rugged and durable structure free of breakable cables and finger manipulating elements. Because the chain saw guard of this invention is a self contained unit, it can lbe readily mounted on existing chain saws.

An advantage of the inventive chain saw guard is that the resilient pad 24 cushions the return of the shield means 13 to the latch position and thereby resists overtravel of the shield to the extent of touching the saw chain 12 which, under normal operative conditions, may still be in motion and thereby cut into or gouge the top of the shield. Gouging of the shield in one prior art chain saw guard is a frequent occurrence under normal operative conditions because of such overtravel of the shield in its return to latch position.

Another advantage of the chain saw guard of this invention is that if the shield does not return toward latch position with suicient momentum to overcome the resistance of pad 24, the chain saw can be swung upwardly to a sudden stop to raise the shield to a position from which it can return with suiiicient momentum to latch. Also the saw can be jerked downwardly to a sudden stop with a similar latching eifect.

Yet another advantage is that the shield means 13 are not unlatched by mere accidental bumping of the end portion 7S of the latch release rod 72. The reason for this is the combination of the latch spring '70 and the distance the latch bolt 66 has to move to become unseated from the keeper flange 56. The latch spring 70, when the latch bolt 66 is seated in the latch bolt hole 57 through the keeper flange 56, is preferably under suiiicient compression and the distance the latch bolt 66 has to move is preferably suiiicient so as to require more than the force of a mere accidental lbump to unlatch the shield means.

Other features, advantages, and spe-cie embodiments of this invention will be readily apparent to those in the exercise of ordinary skill in the art after reading the foregoing disclosures. Such specific embodiments are within the scope of the claimed subject matter unless expressly excluded by claim language. Moreover, while a specic embodiment of the chain saw guard of this invention has been described in considerable detail, variations and modifications of this specic embodiment can be effected Without departing from the spirit and the scope of the invention as disclosed and claimed.

We claim:

1. A guard for a chain saw, which comprises:

(l) shield means;

(2) pivotal mounting means for pivotally mounting said shield means on said chain saw, said shield means `being pivotable between a saw chain enclosing, latch position, an adjacent unlatched, rest position, and a saw chain exposed limit position;

(3) latch means for latching said shield means in said latch position;

(4) latch release means comprising a moveable element in the region of the front end of said shield means, said latch release means unlatching said latch means when said guard is moved so as to bring said element into contact with a relatively immoveable object with sufiicient force to move said element from a rst position to a second position;

(5) means for urging said latch mean-s to latch said shield means when in said latch position and for urging said moveable element toward said rst position; and

(6) means for urging said shield means from said latch position toward said rest position.

2. A guard for a chain saw, which comprises:

(l) shield means;

(2) pivotal mounting means for pivotally mounting said shield means on said chain saw, said shield means being pivotable between a saw chain enclosing, latch position, an adjacent unlatched, rest position, and a saw chain exposed limit position;

(3) means for urging said shield means when out of said latch position to at least said rest position;

(4) latch means for latching said shield means in said latch position;

(5) latch release means comprising a moveable member having an end portion adjacent to, but spaced from, the front of said shield means, and a longitudinal portion in combination with said end portion and said latch means, said latch release means unlatching said shield means when said end portion is pressed against a relatively immoveable object and moved longitudinally backwardly from a first position to a second position;

(6) means for urging said latch means to latch said shield means when in said latch position and for urging said end portion of said latch release means toward said rst'position; and

(7) means urging said shield means from said latch position toward said rest position.

3. A guard for a chain saw, which comprises:

(l) shield means comprising a shield for enclosing at least the sides of the saw chain of said chain saw;

(2) pivotal mounting means for pivotally mounting said shield means on said chain saw, said shield means being pivotable between a saw chain enclosing, latch position, an adjacent unlatched, rest position, and saw chain exposed limit position;

('3) spring means for urging said shield means when Ibetween said limit position and said rest position to at least said rest position;

(4) latch' means for latching said shield means in said latch position;

(5) latch release means comprising `rod means having an end portion adjacent to, but spaced from, `the front of said shield, and a longitudinal portion joined to said end portion and in combination with saidllatch means, said rod means unlatching said latch means when said end portion is pressed against a relatively immoveable object and moved longitudinally backwardly from a lfirst position t-o a second position;

(6) means for urging said latch means to latch said shield means when in said latch position and for urging said end portion of said rod means toward said iirst position; and

(7) means for urging said shield means from said latch position toward said rest position.

4. A guard for a chain saw, which comprises:

(l) shield means comprising a shield for enclosing the sides, top and front end of the saw chain of said chain saw;

(2) pivotal mounting means for pivotally mounting said shield means on said chain saw, said shield means being pivotable between a saw chain enclosing, latch position, an adjacent lunlatched, rest position, and a saw chain exposed limit position, said pivotal mounting means comprising chain saw mounting bracket means and support bracket means transversely hinged by hinge means and fastened to said shield in the region of its back end;

(f3) spring means for urging said shield means when between said limit position and said rest position to at least said rest position;

(4) latch means for latcbing said shield means in said latch position, said latch means comprising latch bolt means and keeper means, said latch bolt means being in combination ywith said support bracket means and having a longitudinally disposed and slideable lat-ch bolt, said keeper means being in lcombination with said chain saw mounting bracket means and having a keeper in front of said latch bolt, said keeper having an opening for receiving said bolt when said support bracket means and said shield means are in latch position;

(5) latch release means comprising a rod having an end portion adjacent to, but spaced from, the front end of said shield, and a longitudinal portion disposed adjacent said top of said shield and extending from said end portion to` the region of said latch bolt, `and further comprising lin-k means connecting said longitudinal portion to said latch bolt, said rod functioning to slide said latch bolt out of said keeper when said end portion is pressed against a relatively immoveable object and moved longitudinally backwardly a first position to a second position;

(6) spring means in combination with said latch means, for urging said latch bolt into said keeper when said keeper is in receiving position relative to sa-id latch bolt, and thus said end portion toward said first position; and

` (7) means for urging'said shield means from said latch position toward said Vrest position.

`5. A guard according to claim 4 wherein said mounting bracket comprises a web, said support bracket comprises fa web adjacent said web of said mounting bracket means when said support bracket and said shield means are in latch position, and said hinge lmeans are in combination with said webs at the back ends thereof.

6. A guard according to claim 5 wherein said means for urging said shield means when in latch position toward said rest position comprise a pad of resilient material disposed between said Webs, said pad having suii- `cient thickness and resiliency to move said shield means from latch position to unlatched, rest position when said latch bolt is slidea'bly removed from said keeper.

'7. A guard according to claim 5 wherein said means for urging said shield means from said latch position toward said rest position comprise spring means.

8. A chain saw comprising .a saw chain guard which comprises:

(l) shield means; n

(2) pivotal mounting means `for pivotally mounting said shield means onV said chain saw, said shield means being pivotable between a saw chain enclosing, latch position, in an adjacent unlatched, rest position, .and a saw chain exposed limit position;

(13) latch means for latching said shield means in said latch position;

(4) latch release means comprising a moveable element in the region of the front of said shield means, said latch release means unlatching said latch means When said saw is moved so asto bring said moveable element into contact with a relatively immoveable object with suiiicient force to move said element from a tirst position to .a second position;

y'(5) means for urging said latch means to latch said shield Imeans when in said latch position and for urging said moveable element toward said iirst position; and

(6) means for urging said shield means from said latch position toward said rest position.

9. A chain saw comprising a saw chain guard which comprises:

(l) shield means;

(2) pivotal mounting means for pivotally mounting said shield means on said chain saw, said shield means being pivotable between a saw chain enclosing, latch position, an adjacent unla-tched, Irest position anda saw chain-exposed limit position;

(3) means for urging said shield means when out of said latch position to at least said rest position;

(4) latch means for latching said shield means in said latch position;

(5) latch release means comprising a moveable member .having an end portion adjacent to, but spaced from, the front of said shield means, and a longitudinal portion in combination with said end portion and said latch means, said latch release means unlatching said shield means when said end portion is pressed -against a relatively immoveable object and moved longitudinally backwardly from a first position to a second position;

(6) means for urgin-g said latch means to latch said shield -means when in said latch position and for urging said end portion of said latch release means toward said first position; and

(7) means for urging said shield means from said latch position toward said rest position.

10. A chain saw comprising a saw chain guard which comprises:

(l) shield means comprising a shield for enclosing at least the sides of the saw chain of said chain saw;

(2) pivotal mountingvmeans for pivotally mounting said shield means on said chain saw, said shield means being pivotable between a saw chain er1- closing, latch position, an adjacent unlatched, rest position, and a saw chain exposed limit position;

(3) spring means for urging said shield means when between said limit position and said rest position to at least said rest position;

(4) latch means for latching said shield means in said latch position;

(5) latch release means comprising rod means having an end portion adjacent to but spaced from, the front of said shield and a longitudinal portion joined to said end portion and in combination with said latch means, said rod means unlatching said latch means when said end portion is pressed against a relatively immoveable object and moved longitudinally backwardly from a first position to a second position;

(6) means for urging said -latch means to latch said shield means when -in said latch position and for urging said end portion of said rod means toward said -tirst position; and

(7) means for urging said shield means from said latch position toward said rest position.

11. A chain saw comprising a saw chain guard which comprises:

(l) shield means comprising a shield for enclosing the sides, top and front end of the saw chain of said chain saw;

(2) pivotal mounting means for pivotally mounting7 said shield means on said chain saw, said shield means being pivotable between a saw chain enclosing, latch position, an adjacent unlat-ched, rest position, and a saw chain exposed limit position said pivotal mounting means comprising chain saw mounting bracket means and support bracket means transversely hinged by hinge means and fastened to said shield in 4the region of its back end;

(3) spring means for urging said shield means when between said limit position and said rest position to at least said rest position;

(4) latch means for latching said shield means in said latch position, said latch means comprising latch bolt means and keeper means, said latch bolt means being in combination -with said support bracket means and having a longitudinally disposed and slideable latch bolt, said keeper means being in combination with said chain saw mounting bracket l@ means and having a keeper in front of said latch bolt, said keeper having an opening for receiving said -bolt when said support bracket means and said shield means are in latch position;

(5) latch release means comprising a rod having an end portion adjacent to, but spaced from, the front end of said shield, and a longitudinal portion disposed adjacent said top of said shield and extending from said end portion to the region of said latch bolt, and further comprising link means connecting said longitudinal portion to said latch bolt, said rod functioning to slide said latch bolt out or said keeper when said end portion is pressed against a relatively immovable object and moved longitudinally backwardly from a rst position to a se-cond position;

(6) spring means in combination with said latch means, for urging said latch bolt into said keeper when said keeper is in receiving position relative to said latch bolt, and thus said end lrod portion toward said rst position; and

(7) means for urging said shield means from said latch position toward said rest position.

12. A chain saw according to claim 11, wherein said mounting bracket means comprises a web with a pair of spaced legs, one fastened to one side lof said support for said saw chain, the other fastened to the other side of said support for said saw chain, said support bracket comprises `a web adjacent said web of said support bracket means when said support bracket and said shield means are in latch position, and said hinge means ,are in combination with said webs at the back ends thereof.

13. A chain saw according to claim 12, wherein said means for urging said shield means from said latch posiltion toward said rest position comprise a pad of resilient material disposed between said webs, said pad having suicient thickness and resiliency to move said shield means from latch position to unlatched rest position when said latch bolt is slideably removed from said keeper.

References Cited UNITED STATES PATENTS 3,230,987 l/l966 Woleslagle l43--32 DONALD R. SCHRA'N, Primary Examiner. 

1. A GUARD FOR A CHAIN SAW, WHICH COMPRISES: (1) SHIELD MEANS; (2) PIVOTAL MOUNTING MEANS FOR PIVOTALLY MOUNTING SAID SHIELD MEANS ON SAID CHAIN SAW, SAID SHIELD MEANS BEING PIVOTABLE BETWEEN A SAW CHAIN ENCLOSING, LATCH POSITION, AN ADJACENT UNLATCHED, REST POSITION, AND A SAW CHAIN EXPOSED LIMIT POSITION; (3) LATCH MEANS FOR LATCHING SAID SHIELD MEANS IN SAID LATCH POSITION; (4) LATCH RELEASE MEANS COMPRISING A MOVEABLE ELEMENT IN THE REGION OF THE FRONT END OF SAID SHIELD MEANS, SAID LATCH RELEASE MEANS UNLATCHING SAID LATCH MEANS WHEN SAID GUARD IS MOVED SO AS TO BRING SAID ELEMENT INTO CONTACT WITH A RELATIVELY IMMOVEABLE OBJECT WITH SUFFICIENT FORCE TO MOVE SAID ELEMENT FROM A FIRST POSITION TO A SECOND POSITION; (5) MEANS FOR URGING SAID LATCH MEANS TO LATCH SAID SHIELD MEANS WHEN IN SAID LATCH POSITION AND FOR URGING SAID MOVEABLE ELEMENT TOWARD SAID FIRST POSITION; AND (6) MEANS FOR URGING SAID SHIELD MEANS FROM SAID LATCH POSITION TOWARD SAID REST POSITION. 